Yes, you are close, very close. Thank you for analysing this so well! Absolutely correct that I was sickened on behalf of my guest, even guests everywhere.
And yes, I did think it was a notification I hadn’t seen before, given the age and decrepit old chrome book I had been using; that using a newer machine was allowing newer notifications through.
In the UK, many people have the Cambridge Analytica scandal wired into their heads, along with the on-line profiling of how people might vote in the Brexit referendum by Facebook, and subsequent influencing of the electorate.
It’s not difficult to start moving such suspicions/understanding into other spheres these days!